Hi,

My small brother, 11, is trying to burn (he calls training) his two
Labrador Retrievers, and he has decided to involve me and anyone else
around.

He wants to build two virtual pet collars made of two small boxes each
(the size of a cellullar phone or smaller if possible). One for each
dog and one for him (both personal boxes may be fit together or not)

Both boxes should beep or vibrate when they are separated by more
than, say, 5,10 or 20 meters/yards, depending on a little switch.

His requirements are almost those of the U.S. Army:

Wireless, mobile and lightweight.
Omnidirectional (no aiming and no line of sight).
Waterproof.
Bulletproof (you know how dangerous are - KIDS not DOGS ;) )
Cheap (I'm afraid I'm going to have to be the sponsor :( )
Independent (dogs should be independent of each other)
Standard battery powered (AAA would be great)
Last a few hours (can reload daily)
Not a dog burner (this requirement added by me, we love the dogs)

My electronics knowledge is quite limited although I might solder
components on a stripboard with a proper and complete diagram. I would
then fit the gadgets in custom made plastic boxes for isolation (to
make them waterproof).

Boxes would be wearable both by my brother and the dogs.

Thanks in advance.

What is brother trying to accomplish exactly, other than animal
cruelty?  (Thank God you have kindess.)  By the way, at age 11, you
should limit his power over other living things.  (Maybe you can give
hime some plants to torture.

Best of luck.

Nelson,

Of course he is not torturing our dogs. 

He is just playing faking he trains dogs for blind people.

I know he may be too young for that but believe me, I am going to help him.

I myself use to monitor his activities with the dogs and both dogs
show normal behaviours.

Beeps are used often in dog training for rewarding the dog as cookies
are useless in some scenarios.

Before making such horrible accusations you should get informed
because you made a big mistake this time.

You are a dangerous undocumented person who covers behind the Internet
anonimity to say stupid things about a child and an activity you know
nothing about.

Think twice again before posting nonsense.

Regards.

I wonder if this device might meet your brother's needs:

http://www.kmhproducts.com/

Unless you had great skill in electronics, self build wouldn?t work
even if you had a circuit diagram. RF is specialised at the best of
times and what would basically amount to radar is probably beyond your
self-professed skills I?m afraid. One could design using ultrasonics
but again one really needs specific skills and equipment. Best to go
with the sage pink?s found unit.

It won?t be perfect as it works on signal strength and various factors
such as orientation will change the range. But still a good product
for the price.

BTW, I don?t think your previous commenter meant to offend. Levity is
easy to misinterpret in the written word :-)

Best

"Dangerous undocumented".  You are anonymous so you can post stupid
comments.  What the hell did you mean by "burn the dogs"?  Maybe you
should explain yourself and not use lingo that can be misinterpreted.

Thanks a lot pink.

It would be something similar but should be programmable.

Instead of that device it should beep (an ultrasound) to reward the
dog when he is doing fine and nothing when he walks away (something
like that, I should check with a professional trainer)

The philosophy, size, features and price would be great.

Great comment.

Any ideas how it is done? Maybe I can modify one of those to our needs.

Regards.